Catheter device and method for delivering a dose internally during minimally-invasive surgery

ABSTRACT

A catheter handpiece apparatus and method for delivering a desired dose with minimal potential for contamination of the injected substance and rapid, accurate delivery of the desired dose. In one embodiment, a carriage assembly affixed to an inner lumen is slidably located within a handpiece housing equipped with an outer lumen. The carriage assembly receives a dose carpule. An actuator knob cocks the carriage assembly and a spring-powered actuator mechanism. After the catheter is maneuvered to a desired injection site and a desired dose is set, depressing a first trigger causes the inner lumen tip to extend beyond the outer lumen into the injection site. Depressing a second trigger causes the actuator mechanism to push the desired dose from the dose carpule through the inner lumen into the injection site. A second embodiment provides a catheter handpiece with a carriage assembly cocking lever and an operator-powered dose delivery mechanism.

TECHNICAL FIELD

[0001] The present invention regards a catheter device and method forthe delivery of medication to a desired location within a patient'sbody. More specifically, the present invention regards a device andmethod for reliable, simple and efficient delivery of a desired dose ofmedication to tissues within the body during minimally-invasive surgeryprocedures whereby a catheter handpiece is configured for deployment ofa needle by the pressing of a single trigger and delivery of a desireddose of medication by pressing of another trigger.

BACKGROUND

[0002] The deployment in the body of medication and other substances,such as materials useful in tracking biological processes throughnon-invasive imaging techniques, is an often repeated and advantageousprocedure performed during the practice of modem medicine. Suchsubstances may be deployed in either case through non-invasiveprocedures such as endoscopy and through more invasive procedures thatrequire larger incisions into the body of a patient. The non-invasiveand less-invasive procedures are generally used when the target area isaccessible through a lumen of the body, while the more invasiveprocedures may be employed when the target area is located deep withinthe body or otherwise not readily accessible through a lumen of thebody.

[0003] Previously, injection of medication in minimally-invasiveprocedures required, among other complications, careful, time-consumingmanual monitoring of the placement of the catheter tip within the bodyand the amount of medication or other substance being delivered duringthe injection procedure, potential exposure of the medication and othersubstances to the atmosphere during the handling of containers inpreparation for dose injection, and, in the case of injection ofmultiple medications or other substances, time-consuming work to eitherremove and replace the catheter dose injection equipment or to preparethe equipment for re-use.

SUMMARY OF THE INVENTION

[0004] The present invention is directed to addressed the foregoingconcerns with previous catheter injection systems. In one embodiment ofthe present invention, there is provided a drug delivery device fordelivering a desired dose to an injection site within a patient's body.The device includes a catheter handpiece, wherein the catheter handpiecehas an outer handpiece body and an inner carriage assembly, and theinner carriage assembly can slide between a lumen end and an opposingactuator end of the handpiece body. The carriage assembly is biasedtoward the lumen end of the handpiece body by a spring. The handpiecebody has an aperture through which a dose carpule is inserted to rest inthe carriage assembly. An outer lumen is affixed to the lumen end of thehandpiece body, and an inner lumen is affixed to the lumen end of thecarriage assembly, such that when the carriage assembly slides towardthe lumen end of the handpiece body, the inner lumen slides within theouter lumen a sufficient distance for the distal end of the inner lumento extend beyond the distal end of the outer lumen, exposing aninjection needle tip.

[0005] At the lumen end of the carriage assembly there is a dose carpulereceiving flange. The proximal end of the inner lumen is affixed to thelumen end of the dose carpule receiving flange, which is configured toreceive the dose carpule and guide the desired dose from the dosecarpule into the inner lumen when a dose delivery actuator at theactuator end of the carriage assembly causes a dose delivery actuator topush on a piston within the dose carpule. Adjacent to the lumen end ofthe dose actuator is a dose carpule pressing block which presses thedose carpule toward the dose carpule receiving flange when an aperturedoor covering the handpiece body aperture is closed.

[0006] The catheter handpiece is prepared for use by actuation of anactuator cocking member located at the actuator end of the handpiecebody. In this embodiment, the actuator cocking member is a knob whichrotates about an axis parallel to the longitudinal axis of the carriageassembly. When the actuator cocking member is rotated by an operator,the carriage assembly is pulled toward the actuator end of the handpiecebody until captured by the carriage release trigger, and a dose deliveryactuator tube is rotated until captured by the dose release trigger.During the movement of the carriage assembly and the dose deliveryactuator tube, the dose delivery actuator rod is prevented from beingretracted by a ratchet mechanism. Once the catheter is located at thedesired injection site within the patient's body, the carriage releasetrigger may be actuated, whereupon the carriage assembly is releasedfrom its cocked position and slides toward the lumen end of the body,thereby extending the distal end of the inner lumen beyond the distalend of the outer lumen and causing the attached injection needle topenetrate the tissue at the desired injection site. Following deploymentof the inner lumen, the dose release trigger may be actuated, whereuponthe dose delivery actuator is released from its cocked position and aspring causes the dose actuator tube to rotate, which advances theactuator rod by means of a threaded dose delivery actuator nut throughwhich the actuator rod passes toward the actuator end of the dosecarpule. The actuator rod thus applies a force to the carpule piston tocause the desired dose to be delivered from the dose carpule through thedose carpule receiving flange and the inner lumen to the desiredinjection site. The amount of dose delivered is controlled by a dosemetering member, which limits the motion of the dose delivery actuatortube, nut and rod, and thereby limits amount of medication dischargedfrom the dose carpule. Following injection of the desired dose, thecatheter handpiece may be cocked, withdrawing the inner lumen andinjection needle back within the outer lumen. The catheter then may berepositioned to another desired injection location within the patient'sbody for delivery of an additional dose from the installed dose carpulein the manner described above. The dose delivery process may be repeateduntil the desired number of doses have been delivered from the carpule,or the carpule is spent, whichever occurs first. When no further dosesare to be delivered from the dose carpule, the catheter handpiece may becocked to withdraw the inner lumen tip into the outer lumen prior toremoval of the catheter from the patient's body.

[0007] In a second embodiment of the present invention, the actuator isnot powered by a spring, but instead the actuator rod moves toward thecatheter end of the carriage assembly, thereby contacting and advancingthe dose carpule piston, by manual turning of the actuator advancingknob at the actuator end of the handpiece body. Cocking of the needlerelease mechanism is accomplished by manual squeezing and pivoting of acocking lever.

[0008] The present invention further includes a method for deliveringthe desired dose to a desired injection location. The method includes:(a) inserting a dose carpule through an aperture in the catheterhandpiece affixed to the catheter into the carriage assembly and closingthe aperture door in order to urge the dose carpule toward a receivingflange on the carriage assembly; (b) priming the inner lumen to removeair therein by setting a desired dose setting on a dose metering memberin the handpiece body, rotating the actuator cocking knob on the end ofthe catheter handpiece opposite the catheter until the carriage assemblyand the dose delivery actuator are in their respective cocked positions,depressing the carriage release trigger to cause the carriage assemblyto slide toward the lumen end of the catheter handpiece, and depressingthe dose release trigger to cause the dose actuator rod to apply a forceto the dose carpule to cause the substance to be injected therein topass from the dose carpule through the dose receiving flange and thoughthe inner lumen and reach the end of the injection needle tip (thissequence is repeated until the medication reaches the injection needletip); (c) rotating the actuator cocking knob on the end of the catheterhandpiece opposite the catheter until the carriage assembly and the dosedelivery actuator are in their respective cocked positions; (d)inserting the catheter including an outer lumen and an inner lumen intoa patient's body and maneuvering the catheter to a desired doseinjection site; (e) depressing the carriage release trigger to cause thecarriage assembly to slide toward the lumen end of the catheterhandpiece and thereby cause the inner lumen affixed to the carriageassembly to extend beyond the distal end of the outer lumen into thedesired injection site; and (f) depressing the dose release trigger tocause the dose actuator rod to apply a force to the dose carpule tocause the desired dose to pass from the dose carpule through the dosereceiving flange, though the inner lumen and its injection needle tipand be deposited at the desired injection site. Alternatively, insteadof depressing a dose release trigger, when using a non-spring poweredembodiment of the present invention, the operator may advance the doseactuator rod toward the dose carpule by manually rotating the actuatoradvancing knob. Following dose delivery, the catheter handpiece may becocked, withdrawing the inner lumen and injection needle back within theouter lumen. The catheter then may be repositioned to another desiredinjection location within the patient's body for delivery of anadditional dose by resetting the desired dose, depressing the needlerelease trigger, and depressing the dose release trigger or, in thesecond embodiment, turning the actuator advancing knob in the mannerdescribed above. The dose delivery process may be repeated until thedesired number of doses have been delivered from the carpule or thecarpule is spent, whichever occurs first, at which point the catheterhandpiece may be cocked to withdraw the inner lumen tip into the outerlumen prior to removal of the catheter from the patient's body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a side view of a catheter handpiece in accordance with afirst embodiment of the present invention.

[0010]FIG. 2 is a view of the internal arrangement of a lower portion ofthe catheter handpiece housing and the carriage assembly in accordancewith a first embodiment of the present invention.

[0011]FIG. 3 is a view of an upper portion of the catheter handpiecehousing and the dose carpule insertion aperture door in accordance witha first embodiment of the present invention.

[0012]FIG. 4 is a view of the carriage assembly in accordance with afirst embodiment of the present invention.

[0013]FIG. 5 is an exploded view of the carriage assembly showingcomponents which cooperate with the dose delivery actuator to permit itsoperation in accordance with a first embodiment of the presentinvention.

[0014]FIG. 6 is an oblique view of a catheter handpiece in accordancewith a second embodiment of the present invention.

[0015]FIG. 7 is an oblique phantom view of a catheter handpiece and itscarriage assembly in accordance with an second embodiment of the presentinvention.

[0016]FIG. 8 is an exploded view of the carriage assembly in accordancewith a second embodiment of the present invention.

DETAILED DESCRIPTION

[0017] FIRST EMBODIMENT. FIG. 1 is a side view of a catheter handpiece 1of a first embodiment of the present invention. The handpiece housing 2in this embodiment may be made from any biocompatible and sufficientlyrigid material including plastic and hard rubber. As shown in FIG. 1,catheter handpiece 1 has at its actuator end 3 an actuator knob 4 forcocking the catheter handpiece. Toward catheter handpiece lumen end 5,there is a dose carpule insertion aperture 6 with an aperture door 7. Inthis embodiment, there is also provided near dose carpule insertionaperture 6 a rubber grip surface 8 to enhance operator control of thehandpiece. Toward actuator end 3 of the catheter handpiece there is adose metering member 9 which is used to set the amount of dose desiredto be injected into the patient when the catheter handpiece isactivated. Next to dose metering member 9 is a replaceable dose meteringlabel 10 to provide the operator with an indication of the amount ofdose that will be injected at various settings of dose metering member9. Dose metering label 10 may be replaced as necessary to ensure thedose selected with dose metering member 9 corresponds to the dosedelivered by the particular dose carpule being used.

[0018]FIG. 1 further shows a catheter affixed at its proximal end to thelumen end 5 of the handpiece, comprising an outer lumen 11 and a strainrelief member 12. An inner lumen resides within outer lumen 11, and isaffixed at its proximal end to a carriage assembly slidably locatedwithin handpiece housing 2 (inner lumen 13 and carriage assembly 14 areshown in FIG. 2 and discussed further, below). The catheter is insertedinto a patient's body and maneuvered to the desired injection site usingtechniques well known to practitioners. Once properly positioned, acarriage assembly release trigger 15 releases carriage assembly 14,which slides toward lumen end 5 of catheter handpiece 1 and therebyextends the distal end of inner lumen 13 and an injection needle tip atthe end thereof (not shown) beyond the distal end of outer lumen 11 andinto tissue at the desired dose injection site. Catheter handpiece 1also contains a dose delivery actuator trigger 16, which releases a dosedelivery actuator within the carriage assembly to permit a dose deliveryactuator rod to apply a force to a dose carpule 17 (specifically, tocarpule piston 17B), thereby causing the desired dose to pass from thedose carpule through inner lumen 13 to the desired injection site (dosedelivery actuator 18 and dose carpule 17 are shown in FIG. 2).

[0019]FIG. 2 is a view of the internal arrangement of a portion of thecatheter handpiece housing 1 and carriage assembly 14 in accordance witha first embodiment of the present invention. As shown in FIG. 2,carriage assembly 14 is slidably located within handpiece housing member19 such that carriage assembly 14 can slide between lumen end 5 andactuator end 3 of the catheter handpiece housing. A spring 20 isconnected at one end to carriage assembly 14 and at its other end tohandpiece housing member 19, and biases carriage assembly 14 towardlumen end 5 of the catheter handpiece housing. At the carriageassembly's lumen end 21 there is a dose carpule receiving flange 22, towhich the proximal end of inner lumen 13 is affixed. As in FIG. 1, outerlumen 11 is shown affixed via strain relief member 12 to lumen end 5 ofhandpiece housing member 19.

[0020] The face of dose carpule receiving flange 22 opposite inner lumen13 is tapered to receive a mating tapered protrusion (not shown) at thefront of dose carpule 17 when the carpule is inserted into carriageassembly 14. Once in the carriage assembly, dose carpule 17 is urgedinto mating contact with dose carpule receiving flange 22 by dosecarpule pressing block 23. Referring now to FIGS. 2 and 3, dose carpulepressing block 23 has grooves 24 which engage corresponding engagementpins 25 on handpiece housing aperture door 7, which is slidably locatedwithin a second handpiece housing member 26 such that aperture door 7may slide beneath aperture 6 between open and closed positions byapplying pressure on door operating tab 27. As aperture door 7 is movedfrom the open position to the closed position, door pins 25 engaged indose carpule pressing block grooves 24 cause dose carpule pressing block23 to pivot on carriage assembly 14 about pivot pins 28. Pressing block23 thus rotates toward, and begins pressing against, the end of dosecarpule 17. This motion in turn urges dose carpule 17 into matingcontact with dose carpule receiving flange 22 with a locking cam action.As aperture door 7 continues toward the closed position, door pins 25disengage from dose carpule pressing block grooves 24. In FIG. 2, dosecarpule pressing block 23 is shown in its disengaged position. In FIG.4, dose carpule pressing block 23 is shown in its fully engagedposition, pressing dose carpule 17 into mating contact with dose carpulereceiving flange 22.

[0021] Referring again to FIG. 2, located between dose carpule 17 andactuator end 29 of the carriage assembly is dose delivery actuator rod18, the operating mechanism for which will be described further, below.Dose delivery actuator rod 18 is positioned on carriage assembly 14 suchthat when actuated, the actuator moves toward dose carpule 17, throughdose carpule pressing block 23, and applies a force to dose carpulepiston 17B that causes the medication in dose carpule 17 to pass fromthe carpule through dose carpule receiving flange 22 and inner lumen 13,into the desired injection site within the patient's body.

[0022] Also shown in FIG. 2 is actuator knob 4 at actuator end 3 ofhandpiece housing member 19. Actuator knob 4 is located by a flangeadjacent to the end of housing member 19, such that the knob may berotated about an axis parallel to a longitudinal axis of carriageassembly 14. Actuator knob 4 has around its outer periphery a spring 30attached at one end to actuator knob 4 and at its other end to handpiecehousing member 19, such that spring 30 returns actuator knob 4 to a restposition following the knob's use to cock the catheter handpiece priorto dose delivery. The inner diameter of actuator knob 4 is sufficientlylarge to surround the actuator end 29 of carriage assembly 14.

[0023] Additional features shown in FIG. 2 include dose metering member9, which in this embodiment is captured between the two catheterhandpiece housing members 19 and 26 during assembly of the housing. Dosemetering member 9 is configured such that its inner surface cooperateswith the carriage assembly's actuator mechanism to limit the travel ofthe dose delivery actuator, and thus dose delivery actuator rod 18,thereby limiting the dose delivered from dose carpule 17 to theinjection site dose. Specifically, the inner surface of dose meteringmember 9 has a graduated stepped surface which, in combination with adose stop tab on the dose delivery actuator mechanism, limits dosedelivery to specific, discrete quantities.

[0024] Also shown in FIG. 2 are carriage release trigger 15 and carriageassembly cocking tab 31. Upon cocking catheter handpiece 1, carriageassembly 14 slides toward the actuator end of handpiece housing 19 untila carriage assembly cocking tab 31 is caught and releasably held bycarriage release trigger 15.

[0025]FIG. 5 shows an exploded view of carriage assembly actuatormechanism. Carriage assembly 14 has a lower member 32 and upper member33 between which the components of the dose delivery actuator mechanismreside. On the outside of carriage assembly members 32 and 33, adjacentto actuator end 29, is a stepped helical ridge 34. Helical ridge 34cooperates with a corresponding tab within the inner diameter ofactuator knob 4 (not shown) such that as actuator knob 4 is rotated, thetab within the knob slides along ridge 34, pulling carriage assembly 14toward the actuator end 3 of catheter handpiece 1 until dose carriagecocking tab 31 is captured by carriage assembly release trigger 15.

[0026] The following describes the arrangement and operation of the dosedelivery actuator in the first embodiment of the present invention. Dosedelivery actuator rod 18 in this embodiment has external threads alongits length which engage corresponding internal threads in a hole in thecenter of dose delivery actuator nut 35. Actuator nut 35 also has acircumferential groove 36 that rests against indexing surfaces 37 in theinterior of carriage assembly members 32 and 33 (indexing surface withinmember 33 not shown) and the face 38 of actuator tube 39, such thatactuator nut 35 is constrained from moving toward the lumen end 21 oractuator end 29 of the carriage assembly. As a result of thisarrangement, actuator nut 35 may only rotate about the longitudinal axisof dose delivery actuator rod 18. Due to the interaction between thethreads on dose delivery actuator rod 18 and the threads in actuator nut35, when actuator nut 35 rotates about dose delivery actuator rod 18,the actuator rod moves toward lumen end 21.

[0027] Actuator nut 35 further has ratchet teeth 40 formed on both sidesof its outer circumference adjacent to circumferential groove 36.Actuator nut ratchet teeth 40 are releasably engaged, on one side ofcircumferential groove 36 by the engagement of a ratchet pawl 45 oncarriage assembly member 33, and on the other side of the nut bycorresponding ratchet hooks 41 within the face of lumen end of actuatortube 39. The actuator nut ratchet teeth 40 on both sides ofcircumferential groove 36 are arranged in same direction, such that whenratchet pawl 45 is engaged with one row of teeth 40, actuator nut 35cannot rotate in a clockwise direction viewed from the lumen end of thecarriage assembly.

[0028] Dose delivery actuator rod 18 has at its actuator end asquare-head 42 which engages a corresponding recess within substantiallythe entire length of dose delivery actuator drive nut 43. Actuator drivenut 43 in turn rests concentrically within dose delivery actuator spring44 and dose delivery actuator tube 39. One end of actuator spring 44engages holes in tabs 46 on the end of actuator drive nut 43, while theother end of the spring engages a hole on an interior surface withinactuator tube 39, such that when actuator tube 39 is turned relative toactuator drive nut 43, energy is stored in actuator spring 44.Engagement tabs 46 at the end of actuator drive nut 43 also serve toengage actuator drive nut slot 47 in carriage assembly lower member 32,such that dose drive nut 43 cannot rotate relative to carriage assembly14.

[0029] The dose delivery actuator is cocked by turning actuator knob 4,which is internally configured to simultaneously cooperate with the endof actuator tube 39 and carriage assembly 14. As actuator knob 4 isturned counter-clockwise viewed from the lumen end of carriage assembly14, the carriage assembly is drawn toward the actuator end of catheterhandpiece housing 1 and releasably held by carriage assembly releasetrigger 15 in the manner previously described. Simultaneously, thecounter-clockwise rotation of actuator knob 4 rotates actuator tube 39,causing ratchet teeth 41 on the face of actuator tube 39 to ratchet overratchet teeth 40 on actuator nut 35, storing energy in spring 44, whilealso permitting dose delivery actuator trigger 16 to capture actuatortube 39 in its cocked position. Actuator nut 35 is prevented fromrotating with actuator tube 39 by the engagement of ratchet pawl 45 oncarriage assembly member 33 with the distal teeth of actuator nut 35.The pitch of the internal and external threads of actuator nut 35 anddose delivery actuator rod 18 are selected to achieve the desired rangeof axial motion of dose delivery actuator rod 18 within a relativelyshort arc of actuator tube 39 rotation when the stored energy in spring44 is released by activating dose release trigger 16.

[0030] Upon reaching the fully cocked position, release of actuator knob4 by the operator will result in actuator knob biasing spring 30rotating the knob clockwise back to its rest position. After the cockingof the catheter handpiece and before triggering dose delivery, thedesired dose setting may be set by sliding dose metering member 9 to theappropriate dose setting as indicated on dose label 10.

[0031] The following describes the operation of the dose deliveryactuator to deliver the desired dose after the actuator mechanism iscocked in the manner described above. Following release of carriageassembly 14 from its cocked position by depression of carriage releasetrigger 15, an operator may depress dose delivery trigger 16 to causethe desired dose to be delivered. Depression of dose delivery trigger 16causes its hook end to pivot clear of actuator tube 39. Due to theenergy stored in actuator spring 44, actuator tube 39 and actuator nut35 (which are engaged by ratchet teeth 40 and 41) begin to rotateclockwise. The clockwise rotation of actuator nut 35 drives dosedelivery actuator rod 18 toward, and into contact with, carpule piston17B, forcing at least a portion of the contents of the carpule into dosecarpule receiving flange 22 and thence through inner lumen 13 to thedesired injection site. The clockwise rotation of actuator nut 35 andaxial motion of dose delivery actuator rod 18 continue until dosemetering stop tab 40 reaches the step on inner surface of dose meteringmember 9 corresponding to the desired dose. When dose metering stop tab40 reaches the selected dose stop step, the clockwise rotation ofactuator tube 39 and actuator nut 35 and the axial motion of dosedelivery actuator rod 18 toward the lumen end of carriage assembly 14are halted, completing the delivery of the desired dose.

[0032] Associated with the foregoing embodiment of the present inventionis a method for delivery of a desired dose using a catheter handpiece ofsignificantly simplified operation. In preparation for delivery of adesired dose of medication or other substance, such as an imaging agent,to a desired injection site within a patient's body, the catheterhandpiece of the first embodiment may be prepared for use by placing adose carpule containing the substance to be injected into the patientthrough carpule insertion aperture 6 and into carriage assembly 14, andthen closing aperture door 7 to cause the dose carpule to be urged intomating contact with dose carpule receiving flange 22. At this time,adhesive dose metering label 10 may be affixed to the catheter handpiecebody adjacent to dose metering member 9 to guide the setting of thedesired dose to be injected, and dose metering member 9 may be set tothe desired dose.

[0033] Next, the catheter handpiece operator cocks the catheterhandpiece by gripping the handpiece in one hand and using the other handto rotating actuator knob 4 clockwise viewed from the actuator knob endof the handpiece until the dose actuator mechanism in carriage assembly14 reaches the end of its travel and actuator knob 4 stops. Upon releaseof actuator knob 4 by the operator, the knob rotates counter-clockwiseback to its starting position.

[0034] Next, the operator depresses carriage assembly release trigger 15and dose delivery trigger 16 to prime the inner lumen with the substanceto be injected. The cocking and firing sequence may be repeated untilthe substance to be injected has reached the distal end of inner lumen13. Once primed, the catheter handpiece may be re-cocked in the mannerpreviously described and the physician may insert the catheter,comprising outer lumen 11 and inner lumen 13, into the patient's bodyand maneuver the catheter to the desired injection site in theconventional manner.

[0035] Once the catheter is located at the desired injection site, thecatheter operator may depress carriage assembly release trigger 15 tocause carriage assembly 14 to slide forward and thus cause the distalend of inner lumen 13 to extend beyond outer lumen 11 into the desiredinjection site. Once inner lumen 13 has been deployed at the desiredinjection site, the catheter operator may depress dose delivery trigger16, thereby permitting dose delivery actuator rod 18 to press on thedose carpule piston 17B and thereby cause the desired dose to pass fromthe dose carpule through dose carpule receiving flange 22 and into innerlumen 13, and thence into the desired injection site. Following deliveryof the desired dose, the catheter handpiece may be cocked, withdrawingthe inner lumen and injection needle back within the outer lumen. Thecatheter then may be repositioned to another desired injection locationwithin the patient's body for delivery of an additional dose in themanner described above. The dose delivery process may be repeated untilthe desired number of doses have been delivered from the carpule or thecarpule is spent, whichever occurs first, at which point the cathetermay be removed from the patient's body.

[0036] SECOND EMBODIMENT. The second embodiment of the present inventionshares the majority of the principal features of the first embodiment,with differences in detail principally due to the second embodiment'sdose delivery actuator being deployed manually by the operator, ratherthan, as in the first embodiment, by utilizing stored spring energy todeploy the dose delivery actuator.

[0037]FIG. 6 is an oblique view of a catheter handpiece in accordancewith a second embodiment of the present invention, showing catheterhandpiece 101, with a lumen end 102 and an actuator end 103. As in thefirst embodiment, handpiece housing 104 may be made from anybio-compatible and sufficiently rigid material including plastic andhard rubber. At its actuator end 103, catheter handpiece 101 has anactuator knob 105 for operating the dose delivery actuator mechanismwithin the catheter handpiece and thereby delivering the desired dose.Toward lumen end 102, there is a dose carpule insertion aperture 106with an aperture door 107, and a dose metering member 108 which is usedto set the amount of dose desired to be injected into the patient whenthe catheter handpiece is activated. Next to dose metering member 108are dose metering markings 109 to provide the operator with anindication of the amount of dose that will be injected at varioussettings of dose metering member 108.

[0038]FIG. 6 further shows a catheter affixed at its proximal end to thelumen end 102 of the handpiece, comprising an outer lumen 110 and astrain relief member 111. An inner lumen resides within outer lumen 110,and is affixed at its proximal end to a carriage assembly slidablylocated within handpiece housing 104 (inner lumen 112 and carriageassembly 113 are shown in FIG. 7 and discussed further, below). Once thecatheter is properly positioned in the patient's body, carriage assemblyrelease trigger 114 releases carriage assembly 113, which slides towardlumen end 102 of catheter handpiece 101 and thereby extends the distalend of inner lumen 112 and an injection needle tip at the end thereof(not shown) beyond the distal end of outer lumen 110 and into tissue atthe desired dose injection site. Catheter handpiece 101 also contains ahandpiece cocking lever 115, which moves carriage assembly 113 into itscocked position. Dose carpule 116 (shown in FIG. 7) is inserted intocatheter handpiece 101 through aperture 106 and placed in carriageassembly 113 with carriage assembly 113 in the uncocked position.

[0039] Reference will now be made to FIG. 7 and FIG. 8 to highlight theprincipal differences in arrangement and operation of the secondembodiment from the first embodiment (arrangements or operations whichare similar between the two embodiments are not again described herein).FIG. 7 is an oblique phantom view of a catheter handpiece and itscarriage assembly in accordance with the second embodiment of thepresent invention, while FIG. 8 is an exploded view of the carriageassembly of the second embodiment.

[0040] As shown in FIG. 7, carriage assembly 113 is slidably locatedwithin handpiece housing 104 such that carriage assembly 113 can slidebetween lumen end 102 and actuator end 103 of the catheter handpiecehousing. A spring 117 is connected at one end to carriage assembly 113and at its other end to handpiece housing 104, and biases carriageassembly 113 toward lumen end 102 of the catheter handpiece housing. Atthe carriage assembly's lumen end 118 there is a dose carpule receivingflange 119, to which the proximal end of inner lumen 112 is affixed.Outer lumen 110 is shown affixed via strain relief member 111 to lumenend 102 of handpiece housing 104.

[0041] As in the first embodiment, a dose delivery actuator rod 120 islocated between dose carpule 116 and actuator end 121 of the carriageassembly. Dose delivery actuator rod 120 is positioned on carriageassembly 113 such that when actuated, the actuator moves toward dosecarpule 116 and applies a force to carpule piston 116B that causes themedication therein to pass from dose carpule 116 through dose carpulereceiving flange 119 and inner lumen 112 to reach the desired injectionsite within the patient's body.

[0042] Additional features shown in FIG. 7 include actuator knob 105 atactuator end 103 of handpiece housing 104. As shown in FIG. 8, actuatorknob 105 has an internal projection 122 extending from its center towardcarriage assembly 113, which contains an axial hexagonal hole. Actuatorknob 105 is coupled to the catheter handpiece through the fitting of anaxial hexagonal hole in projection 122 over a corresponding hexagonalend projection 123 of dose delivery actuator tube 124, and by trappingof a groove 154 in projection 122 between the halves of the handpiecebody. Actuator knob 105 is returned to its rest position after use by aspiral spring 153 concentrically located over internal projection 122.One end of spring 153 engages a hole in the underside of actuator knob105, while the other end of spring 153 engages a hole in handpiecehousing 104 (shown in FIG. 7).

[0043] Returning to FIG. 7, also shown are a number of components whoseoperation will be described further, below, including handpiece cockinglever 115, which is pivotally mounted to handpiece housing 104, pushingarm 125 configured to pivot with handpiece cocking lever 115 and pushescarriage assembly 113 into its cocked position, actuator tube holdbackratchet lever 126, carriage release trigger 114, and carriage assemblytab 127, which is releasably captured by carriage release trigger 114 asthe catheter handpiece is cocked. Within the inner surface of handpiecehousing 104 toward its actuator end 103 is dose delivery blocking ridge128, which cooperates with dose tube safety tab 129 when carriageassembly 113 is in its cocked position to prevent delivery of a dosefrom dose carpule 116 if inner lumen 112 has not been deployed. Finally,FIG. 7 shows dose tube stop tab 130 projecting outward through slot 131in carriage assembly 113 from outside of actuator tube 124. Dose stoptube tab 130 interacts with dose metering steps on an inner surface ofdose metering member 108 (not shown) to halt dose delivery when thedesired amount of medication or other substance has been delivered tothe desired injection location within the patient.

[0044]FIG. 8 shows an exploded view of carriage assembly actuatormechanism of the second embodiment. Carriage assembly 113 has a lowermember 132 and upper member 133 between which the components of the dosedelivery actuator mechanism reside. On the underside of carriageassembly member 132 is a carriage cocking bar 134. When handpiececocking lever 115 is depressed, pushing arm 125 pivots, pushing carriagecocking bar 134 and carriage assembly 113 toward actuator end 103 of thecatheter handpiece until carriage cocking tab 127 on carriage assemblymember 133 is releasably captured by carriage release trigger 114 (shownin FIG. 7). At the beginning of the stroke of handpiece cocking lever115, the initial motion of the lever results in contact with actuatortube holdback ratchet lever 126 (shown in FIG. 7), which is pivotallymounted on carriage assembly 113 such that its holdback pawl passesthrough slot 135 in carriage assembly 113 and engages actuator tuberatchet teeth 136, thereby preventing clockwise rotation of actuatortube 124. When handpiece cocking lever 115 contacts actuator tubeholdback ratchet lever 126, the lever pivots and disengages actuatortube ratchet teeth 136, permitting the actuator tube to rotate clockwiseto ensure it is in its starting position in the dose delivery process.

[0045] The following describes the arrangement of the dose deliveryactuator in the second embodiment of the present invention. As in thefirst embodiment, dose delivery actuator rod 120 has external threadsalong its length which engage corresponding internal threads in a holein the center of actuator nut 137. Actuator nut 137 rests againstindexing surfaces 138 in the interior of carriage assembly members 132and 133 (indexing surface within member 133 not shown) and the face 139of actuator tube 124, such that actuator nut 137 is constrained frommoving toward the lumen end 118 or actuator end 121 of the carriageassembly. As with the first embodiment, actuator nut 137 may only rotateabout the longitudinal axis of dose delivery actuator 120, and actuatornut 137 and dose delivery actuator rod 120 cooperate to permit extensionof actuator rod 120.

[0046] Actuator nut 137 further has ratchet teeth 140 formed on bothsides of its outer circumference adjacent to circumferential groove 141.Actuator nut ratchet teeth 140 are releasably engaged, to one side ofcircumferential groove 141 by a hook 150 on carriage assembly member133, and to the other side of the nut by corresponding ratchet hooks 142within the face of lumen end of actuator tube 124. The actuator nutratchet teeth 140 on both sides of circumferential band 141 are arrangedin the same direction, such that when the ratchet hooks are engaged,actuator nut 137 cannot rotate in a clockwise direction viewed from thelumen end of the carriage assembly.

[0047] Dose delivery actuator rod 120 has at its actuator end asquare-shaped head 143 which engages a corresponding recess withinsubstantially the entire length of dose delivery actuator drive nut 144.Actuator drive nut 144 in turn rests concentrically within actuator tube124. Along the exterior circumference of actuator drive nut 144 aredrive nut holding tabs 145, which pass through slots 146 in actuatortube 124 and engage corresponding recesses in the interior surface ofcarriage assembly member 133 (not shown) to prevent rotation of drivenut 144 during operation of catheter handpiece 101.

[0048] Also shown in FIG. 8 is dose metering stop tab 130 extendingradially from the outside circumference of actuator tube 124 throughdose stop slot 131 in carriage assembly member 133. Dose metering stoptab 130 is positioned along actuator tube 124 such that when the dosedelivery operation is performed, the dose stop tab contacts dosemetering member 108 and stops further dose injection when the desireddose is reached.

[0049] Operation of the catheter handpiece of the second embodimentbegins with the operator depressing handpiece cocking lever 113, whichsimultaneously causes carriage assembly 113 to slide toward the actuatorend 103 of catheter handpiece 101 until carriage assembly tab 127 iscaptured and releasably held by carriage assembly release trigger 114,and causes actuator tube holdback lever 126 to pivot, thereby releasingactuator tube 124 to rotate clockwise by force of actuator knob spring153 to return to its rest position and to permit dose tube safety tab129 to engage dose delivery blocking ridge 128, thereby preventing dosedelivery while the handpiece is cocked.

[0050] Following a physician's insertion of the catheter into thepatient's body and maneuvering of the catheter to the desired injectionsite, the operator depresses carriage assembly release trigger 114,freeing carriage assembly 113 to slide toward lumen end 102 of catheterhandpiece 101, thereby extending the injection needle tip on the distalend of inner lumen 112 into the desired injection site. The movement ofcarriage assembly 113 toward lumen end 102 also allows dose tube safetytab 129, which extends from actuator tube 124, to pass dose deliveryblocking ridge 128 and thereby permit actuator tube 124 to subsequentlyrotate counter-clockwise when operated. In order to deliver the desireddose, actuator knob 105 is manually rotated counter-clockwise by theoperator, which in turn rotates actuator tube 124 (to which actuatorknob 105 is coupled by engagement of knob projection 122 with actuatortube 123) counter-clockwise until dose metering stop tab 130 projectingfrom the outer surface of actuator tube 124 reaches the inner surface ofdose metering member 108. As in the first embodiment, the range oftravel of the actuator tube 124 is relatively short (approximately 45degrees), however, any length of arc less than a complete circle couldbe used as long as the length of dose stop slot 152 is not so great asto compromise the structural integrity of the carriage assembly.

[0051] The counter-clockwise rotation of actuator tube 124 causesactuator nut 137 (whose ratchet teeth 140 are engaged by ratchet hooks142 on face 139 of actuator tube 124) to also rotate counter-clockwisewith actuator tube 124. Due to the interaction of the internal threadsof actuator nut 137 with the external threads on dose delivery actuatorrod 120, actuator nut 137 drives dose delivery actuator rod 120 toward,and into contact with, dose carpule piston 116B. Dose delivery actuatorrod 120 then presses on dose carpule piston 116B to begin forcing thecontents of the carpule into dose carpule receiving flange 119 andthence through inner lumen 112 and the injection needle tip into thedesired injection site. The counter-clockwise rotation of actuator nut137 and axial motion of dose delivery actuator rod 120 continues untildose metering stop tab 130 reaches the step on inner surface of dosemetering member 108 corresponding to the desired dose. When dosemetering stop tab 130 reaches the selected dose stop step, thecounter-clockwise rotation of actuator tube 124 and actuator nut 137 andthe axial motion of dose delivery actuator rod 120 toward the lumen endof carriage assembly 113 are halted, completing the delivery of thedesired dose.

[0052] Associated with the foregoing embodiment of the present inventionis a method for delivery of a desired dose using the catheter handpieceof this embodiment. In order to deliver a desired dose of medication orother substance to a desired injection site within a patient's body, thecatheter handpiece of the second embodiment is be prepared for use byplacing a dose carpule containing the substance to be injected into thepatient through carpule insertion aperture 106 and onto carriageassembly 113, and then closing aperture door 107. Next, in order toprime the inner lumen with the substance to be injected, a sequence ofoperating cocking lever 115, pressing carriage assembly release trigger114 and rotating actuator advance knob 105 is performed as many times asnecessary to cause the substance to be injected to reach the distal endof inner lumen 112.

[0053] Once the substance has reached the end of the inner lumen, thecatheter handpiece may be re-cocked in the manner previously describedand dose metering member 108 set to the desired dose, whereupon thephysician may then insert the catheter, comprising outer lumen 110 andinner lumen 112, into the patient's body and maneuver the catheter tothe desired injection site in the conventional manner. Once the catheteris located at the desired injection site, the catheter operator maydepress carriage assembly release trigger 114 to cause carriage assembly113 to slide forward and thus cause the distal end of inner lumen 112 toextend beyond outer lumen 110 into the desired injection site. Onceinner lumen 112 has been deployed, the catheter operator may rotateactuator knob 105 counter-clockwise viewed from lumen end 102 until dosestop tab 130 on actuator tube 124 reaches the dose stop step on dosemetering member 108 corresponding to the desired dose. Rotation ofactuator knob 105 causes actuator tube 124 to rotate actuator nut 137counter-clockwise, in turn causing dose delivery actuator rod 120 toextend forward to press on dose carpule piston 116B, and thereby causethe desired dose to pass from the dose carpule through dose carpulereceiving flange 119 and inner lumen 112, and thence to the desiredinjection site within the patient's body. Following delivery of thedesired dose, the physician may cock the catheter handpiece to withdrawthe inner lumen tip into the outer lumen, and then may remove thecatheter from the patient's body, or alternatively, if the contents ofthe dose carpule have not all been injected, and another dose may bedelivered to a desired injection site.

[0054] While the present invention has been described with reference towhat are presently considered to be preferred embodiments thereof, it isto be understood that the present invention is not limited to thedisclosed embodiments or constructions. On the contrary, the presentinvention is intended to cover various modifications and equivalentarrangements. In addition, while the various elements of the disclosedinvention are described and/or shown in various combinations andconfigurations, which are exemplary, other combinations andconfigurations, including more, less or only a single embodiment, arealso within the spirit and scope of the present invention.

What is claimed is:
 1. A dose delivery device for delivering a desireddose to an injection site within a patient's body, comprising: ahousing; an outer lumen, a proximal end of which is affixed to a lumenend of the housing; a carriage assembly, slidably located within thehousing; an inner lumen, slidably located within the outer lumen,wherein a proximal end of the inner lumen is affixed to a lumen end ofthe carriage assembly, and a distal end of the inner lumen extendsbeyond a distal end of the outer lumen when the carriage assembly slidestoward the lumen end of the housing; a dose delivery actuator; at leastone cocking member for placing the carriage assembly and the dosedelivery actuator into respective cocked conditions; a carriage assemblyrelease trigger; a dose release trigger; and a dose metering memberoperable from outside the housing, wherein the carriage assembly whenreleased from its cocked condition by the carriage assembly releasetrigger is biased to slide toward the lumen end of the housing, the dosedelivery actuator when released from its cocked condition by the doserelease trigger is biased to apply a force to a dose carpule placed onthe carriage assembly to cause the desired dose to pass from the dosecarpule through the inner lumen, and dose delivery actuator movement ishalted by the dose metering member when the desired dose has beendelivered.
 2. The dose delivery device of claim 1 wherein an inner lumenextension spring biases the carriage assembly toward the lumen end ofthe housing.
 3. The dose delivery device of claim 2, wherein the dosedelivery actuator is located at an actuator end of the carriage assemblyopposite the lumen end.
 4. The dose delivery device of claim 3, whereinthe dose delivery actuator includes a dose delivery actuator rod and anactuator spring which biases the dose delivery actuator rod toward thedose carpule.
 5. The dose delivery actuator of claim 4, wherein thecarriage assembly includes at its lumen end a dose carpule receivingflange in communication with the proximal end of the inner lumen, thedose carpule receiving flange and a lumen end of the dose deliveryactuator are separated by a distance sufficient to accommodate the dosecarpule, and when the dose delivery actuator rod presses on the dosecarpule, the desired dose passes from the dose carpule though the dosecarpule receiving flange into the inner lumen.
 6. The dose deliverydevice of claim 5, wherein the dose delivery actuator further comprises:an actuator drive nut, including a longitudinal recess configured toreceive the dose delivery actuator rod and preclude rotation of theactuator rod relative to the drive nut, and a tab extending radiallyfrom the actuator drive nut and engaging the carriage assembly topreclude rotation of the actuator drive nut relative to the carriageassembly; an actuator tube, including a dose stop tab which cooperateswith the dose metering member to halt actuator tube rotation, and atleast one ratchet pawl located at a lumen end of the actuator tube; andan actuator nut, located adjacent to the lumen end of the actuator tube,including a plurality of ratchet teeth on an external circumferentialsurface, and an internally-threaded axial hole which cooperates withexternal threads on the dose delivery actuator rod, wherein the actuatordrive nut is located within the actuator tube, the actuator spring isconcentrically located therebetween, and the actuator tube engages afirst actuator spring end and the actuator drive nut engages a secondactuator spring end, a first portion of the actuator nut ratchet teethare engaged by a ratchet pawl on the carriage assembly such that theactuator nut is prevented from rotating with the actuator tube duringdose delivery actuator cocking, and a second portion of the actuator nutratchet teeth are engaged by the ratchet pawl at a lumen end of theactuator tube such that when the actuator tube rotates under the bias ofthe actuator spring, the actuator nut rotates with the actuator tube andcauses the dose delivery actuator to advance against the dose carpuleuntil actuator tube rotation is halted by the dose metering member. 7.The dose delivery device of claim 6, wherein the cocking member is anactuator knob located at the actuator end of the housing, wherein theactuator knob rotates about a longitudinal axis of the carriageassembly.
 8. The dose delivery device of claim 7, wherein the actuatorknob further comprises: a knob body; a cylindrical projection on anunderside of the knob body toward the lumen end of the housing, whereinthe inner diameter of the cylindrical projection is larger than an outerdiameter of the actuator end of the carriage assembly, an actuator knobreturn spring, wherein a first knob spring end is connected to theactuator knob and a second knob spring end is connected to the housing,wherein the actuator knob returns to a starting position when released;and at least one inner flange located on an interior surface of thecylindrical projection, wherein the inner flange cooperates with acorresponding helical flange on the outer surface of the carriageassembly; at least one actuator knob engagement surface which cooperateswith a corresponding cocking flange on the dose delivery actuator tube,wherein when the actuator knob is rotated, the at least one actuatorknob engagement surface rotates the actuator tube into a cockedposition, and the at least one inner flange moves the carriage assemblytoward the actuator end of the housing to place the carriage assembly inits cocked condition.
 9. The dose delivery device of claim 5, whereinthe housing includes a dose carpule insertion aperture adjacent to thedose carpule receiving flange, the device further comprising: a dosecarpule insertion aperture cover; and a dose carpule pressing block,wherein the dose carpule pressing block is configured to cooperate withaperture cover and the carriage assembly such that when the aperturecover is closed, the dose carpule pressing block presses the dosecarpule against the dose carpule receiving flange.
 10. A method fordelivery of a desired dose to an injection site within a body of apatient using the dose delivery apparatus claim 1, comprising the stepsof: placing a dose carpule containing a substance to be injected intothe patient's body onto the carriage assembly; setting the desired dosewith the dose metering member; priming the inner lumen with thesubstance to be injected; placing the carriage assembly and the dosedelivery actuator into their respective cocked conditions; inserting theouter lumen into the patient's body and maneuvering the outer lumen tothe desired injection site; releasing the carriage assembly to extendthe distal end of the inner lumen into the desired injection site;releasing the dose delivery actuator to cause the desired dose to passfrom the dose carpule through the inner lumen to the desired injectionsite; withdrawing the outer lumen from the patient's body.
 11. Themethod of claim 10, wherein before the step of withdrawing the catheterfrom the patient's body, the method further comprises the steps of:placing the carriage assembly and the dose delivery actuator into theirrespective cocked conditions; releasing the carriage assembly; andreleasing the dose delivery actuator.
 12. The method of claim 11,wherein after the step of placing the carriage assembly and the dosedelivery actuator into their respective cocked conditions, the methodfurther comprises the step of: repositioning the outer lumen to adifferent desired injection site.
 13. The method of claim 11, whereinbetween the steps of placing the carriage assembly and the dose deliveryactuator into their respective cocked conditions and releasing the dosedelivery actuator, the method further comprises the step of: resettingthe dose metering member to a new desired dose.
 14. A dose deliverydevice for delivering a desired dose to an injection site within a bodyof a patient, comprising: a housing; an outer lumen, a proximal end ofwhich is affixed to a lumen end of the housing; a carriage assembly,slidably located within the housing; an inner lumen, slidably locatedwithin the outer lumen, wherein a proximal end of the inner lumen isaffixed to a lumen end of the carriage assembly, and a distal end of theinner lumen extends beyond a distal end of the outer lumen when thecarriage assembly slides toward the lumen end of the housing; a dosedelivery actuator; at least one cocking member for placing the carriageassembly into a cocked condition and the dose delivery actuator into astarting condition; a carriage assembly release trigger; a dose releaseactuator; and a dose metering member operable from outside the housing,wherein the carriage assembly when released from its cocked condition bythe carriage assembly release trigger is biased to slide toward thelumen end of the housing, the dose delivery actuator when moved from itsstarting condition by the dose release actuator is biased to apply aforce to a dose carpule placed on the carriage assembly to cause thedesired dose to pass from the dose carpule through the inner lumen, anddose delivery actuator movement is halted by the dose metering memberwhen the desired dose has been delivered.
 15. The dose delivery deviceof claim 14 wherein an inner lumen extension spring biases the carriageassembly toward the lumen end of the housing.
 16. The dose deliverydevice of claim 15, wherein the dose delivery actuator is located at anactuator end of the carriage assembly opposite the lumen end.
 17. Thedose delivery device of claim 16, wherein the dose delivery actuatorincludes a dose delivery actuator rod which advances toward the dosecarpule when the dose release actuator is operated.
 18. The dosedelivery actuator of claim 17, wherein the carriage assembly includes atits lumen end a dose carpule receiving flange in communication with theproximal end of the inner lumen, the dose carpule receiving flange and alumen end of the dose delivery actuator are separated by a distancesufficient to accommodate the dose carpule, and when the dose deliveryactuator rod presses on the dose carpule, the desired dose passes fromthe dose carpule though the dose carpule receiving flange into the innerlumen.
 19. The dose delivery device of claim 18, wherein the dosedelivery actuator further comprises: an actuator drive nut, including alongitudinal recess configured to receive the dose delivery actuator rodand preclude rotation of the actuator rod relative to the drive nut, anda tab extending radially from the actuator drive nut and engaging thecarriage assembly to preclude rotation of the actuator drive nutrelative to the carriage assembly; an actuator tube, including a dosestop tab which cooperates with the dose metering member to halt actuatortube rotation, and at least one ratchet pawl located at a lumen end ofthe actuator tube; and an actuator nut, located adjacent to the lumenend of the actuator tube, including a plurality of ratchet teeth on anexternal circumferential surface, and an internally-threaded axial holewhich cooperates with external threads on the dose delivery actuatorrod, wherein the actuator drive nut is concentrically located within theactuator tube, the actuator tube cooperates with the dose releaseactuator to transfer the motion of the dose release actuator to the dosedelivery actuator rod, a first portion of the actuator nut ratchet teethare engaged by a ratchet pawl on the carriage assembly such that theactuator nut is prevented from rotating with the actuator tube duringdose delivery actuator cocking, and a second portion of the actuator nutratchet teeth are engaged by the ratchet pawl at a lumen end of theactuator tube such that when the actuator tube rotates under in responseto operation of the dose release actuator, the actuator nut rotates withthe actuator tube and causes the dose delivery actuator to advanceagainst the dose carpule until actuator tube rotation is halted by thedose metering member.
 20. The dose delivery device of claim 19, whereinthe dose release actuator is a knob located at the actuator end of thehousing, the actuator knob comprising: an knob body; and a projectionfrom an underside of the knob body toward the lumen end of the housing,wherein at least one actuator tube engagement surface cooperates with acorresponding surface of the projection such that rotation of theactuator knob rotates the actuator tube.
 21. The dose delivery device ofclaim 20, wherein the actuator tube engagement surface is an extensionfrom an actuator end of the actuator tube and has a polygonalcross-section which cooperates with a corresponding polygonalcross-section axial recess in the actuator knob projection.
 22. The dosedelivery device of claim 21, wherein the cocking member is a leverpivotally mounted on the housing alongside the carriage assembly andconfigured to cause an actuator tube holdback lever to release theactuator tube to permit movement of the actuator tube to a startingposition, and to push the carriage assembly toward the actuator end ofthe housing until the carriage assembly reaches a cocked position.
 23. Amethod for delivery of a desired dose to an injection site within a bodyof a patient using the dose delivery apparatus claim 14, comprising thesteps of: placing a dose carpule containing a substance to be injectedinto the patient's body onto the carriage assembly; setting the desireddose with the dose metering member; priming the inner lumen with thesubstance to be injected; placing the carriage assembly and the dosedelivery actuator into their respective cocked and starting conditions;inserting the outer lumen into the patient's body and maneuvering theouter lumen to the desired injection site; releasing the carriageassembly to extend the distal end of the inner lumen into the desiredinjection site; operating the dose delivery actuator to cause thedesired dose to pass from the dose carpule through the inner lumen tothe desired injection site; withdrawing the outer lumen from thepatient's body.
 24. The method of claim 23, wherein before the step ofwithdrawing the catheter from the patient's body, the method furthercomprises the steps of: placing the carriage assembly and the dosedelivery actuator into their respective cocked and starting conditions;releasing the carriage assembly; and operating the dose deliveryactuator.
 25. The method of claim 24, wherein after the step of placingthe carriage assembly and the dose delivery actuator into theirrespective cocked and starting conditions, the method further comprisesthe step of: repositioning the outer lumen to a different desiredinjection site.
 26. The method of claim 24, wherein between the steps ofplacing the carriage assembly and the dose delivery actuator into theirrespective cocked and starting conditions and operating the dosedelivery actuator, the method further comprises the step of: resettingthe dose metering member to a new desired dose.